CITI seminar – Martin Kumm (University of Applied Sciences Fulda, Germany) – 13/11 at 10:30AM

Title: Design of Optimal Multiplierless FIR Filters

Date and Place: 13 / 11 / 2019 10:30 in TD-C

Speaker: Martin Kumm (University of Applied Sciences Fulda, Germany)

Host: Florent de Dinechin

In this talk we present a novel method for the simultaneous design of digital filters adhering to a given frequency specification and its dedicated (hardware) implementation. Our methods are based on an integer linear programming (ILP) problem and aim to minimize the number of adders used to implement a digital filter. In the first part, an overview is given about the structure of finite impulse response (FIR) filters which typically contain many costly multiplications. As these are usually multiplications by a constant, they can be reduced to additions, subtractions and bit-shifts, leading to a multiplierless realization. A brief overview of state-of-the-art methods for optimizing constant multiplications is presented. In the second part, novel extensions are presented that also consider the frequency specification of the digital filter in the optimization. Compared to previous multiplierless FIR approaches, the methods introduced here ensure adder count optimality. We show the effectiveness by solving established design problems: our results either prove existing heuristics to be optimal or improve their adder count.

Martin Kumm is full professor in the faculty of Applied Computer Science at the University of Applied Sciences Fulda in Germany. His research interests are arithmetic circuits and their optimization in the context of reconfigurable systems (FPGAs).

CITI Seminar of Erwan Le Merrer / Gilles Tredan (Inria-Rennes / LAAS-CNRS) on October 9 at 3pm

Title: The Bouncer Problem: Challenges to Remote Explainability

Date and Place: 09 / 10 / 2019 3PM in 432 (Antenne Inria)

Host: Privatics

The concept of explainability is envisioned to satisfy society’s demands for transparency on machine learning decisions. The concept is simple: like humans, algorithms should explain the rationale behind their decisions so that their fairness can be assessed. While this approach is promising in a local context (e.g. to explain a model during debugging at training time), we argue that this reasoning cannot simply be transposed in a remote context, where a trained model by a service provider is only accessible through its API. This is problematic as it constitutes precisely the target use-case requiring transparency from a societal perspective. Through an analogy with a club bouncer (which may provide untruthful explanations upon customer reject), we show that providing explanations cannot prevent a remote service from lying about the true reasons leading to its decisions.

More precisely, we prove the impossibility of remote explainability for single explanations, by constructing an attack on explanations that hides discriminatory features to the querying user. We provide an example implementation of this attack. We then show that the probability that an observer spots the attack, using several explanations for attempting to find incoherences, is low in practical settings. This undermines the very concept of remote explainability in general.

Erwan is on an “advanced research position” at Inria, in the WIDE team, since Nov. 2018. He was previously senior research scientist at Technicolor R&I (2009-2018). Gilles is a “chargé de recherches” at CNRS since 2011.

CITI Seminar of Subhash Lakshminarayana (University of Warwick’s School of Engineering) on September 19 at 2pm

Title: On False Data Injection Attacks Against Power Grids and Countermeasures

Date and Place: 19 / 09 / 2019 2PM in TD-C

Host: Samir M. Perlaza

The power grid state estimation (SE) has been shown to be vulnerable to false data injection (FDI) attacks, which can lead to severe consequences, e.g., transmission line trips, unsafe frequency excursions and/or economic losses. In this talk, we will examine the security of power gird SE from both the attacker and the defender’s perspective. For the former, we examine data-driven FDI attacks, i.e., constructing FDI attacks that can bypass the grid’s bad-data detector (BDD) by accessing its measurement data over a period of time. We characterize important tradeoffs for the attacker in this context between the attack’s spatial and temporal efficiency. The results provide us with an understanding for designing defense mechanism to thwart such attacks. For defense, we propose a hardened-attack detector based on moving-target defense (MTD) that actively perturbs transmission line reactances to invalidate the attacker’s knowledge. We present novel formal design criteria to select MTD reactance perturbations that are truly effective. Moreover, based on a key optimal power flow formulation, we find that the effective MTD may incur a non-trivial operational cost. Accordingly, we characterize important tradeoffs between the MTD’s detection capability and its associated required cost. Extensive simulations, using the MATPOWER simulator and benchmark IEEE bus systems, verify and illustrate the proposed design approach.

Subhash Lakshminarayana is an assistant professor in the University of Warwick’s School of Engineering since September 2018. Prior to joining Warwick, he worked as a research scientist at the Advanced Digital Sciences Center (ADSC) in Singapore between 2015-2018. Before that, he held joint post-doctoral researcher appointment at Princeton University and the Singapore University of Technology and Design (SUTD) between 2013-2015. He received his PhD in the field of Wireless Communications at the Department of Telecommunications at Ecole Superieure d’Electricite (Supelec) Paris, France, M.S. degree from The Ohio State University, USA and B.S. from Bangalore University in India. His research interests include cyber-physical system security (power grids and urban transportation) and wireless communications. His works have been selected among the Best Conference Papers at the IEEE Power Energy Society General Meeting (PESGM) 2015 conference, and the Best 50 Papers at the IEEE Globecom 2014 conference.

CITI Seminar of Christine Solnon (INSA-Lyon-LIRIS) on September 26 at 2pm

Title: Time-Dependent and Stochastic Vehicle Routing Problems

Date and Place: 26 / 09 / 2019 14:00 in TD-C

Host: Florent de Dinechin

Smart cities are equipped with sensors which monitor traffic speed. The exploitation of these data to optimise urban deliveries has given rise to new challenging problems, and I’ll focus on two of them: – Time-Dependent Vehicle Routing Problems, which take into account variations of travel speeds during the day; – Stochastic Vehicle Routing Problems, where uncertain data are represented by random variables.

Christine Solnon is Professor in the Computer Science Department of INSA Lyon, and member of the LIRIS lab.

PhD Defence: “Contributions Théoriques sur les Communications Furtives”, David KIBLOFF, Chappe Amphitheater, CITI, 17th of September 2019 at 14h00


Information Theoretic Contributions to Covert Communications


The problem of covert communications, also known as communications with low-probability of detection has gained interest in the information theory community in the last years. Since Bash et. al. showed in 2012 that the square-root law applied in the point-to-point case for such communications systems, the number of contributions on the topic did not cease to grow. In this thesis, two new problems of covert communications are introduced. First, the problem of covert communications over a point-to-point link where a warden observes only a fraction of channel outputs in order to try to detect the communications is studied. An achievability bound in the finite block-length regime is derived for this problem. Second, the problem of embedding covert information into a given broadcast code is introduced. Given a broadcast code to transmit a common message to two receivers, the goal is to determine the maximum number of information bits that can be reliably sent to one receiver while remaining covert with respect to the other receiver. For this problem, both an achievability and converse bound in the asymptotic block-length regime are derived for a particular class of channels, i.e., symmetric channels. Together these bounds characterize the maximum number of information bits that can be covertly embedded in a given broadcast code for symmetric channels.



  • Dr. Albert Guillen i Fabregas, Université Pompeu Fabra, Espagne. Rapporteur.
  • Dr. Aline Roumy, INRIA, France. Rapporteure.
  • Dr. Laurent Clavier, IMT Lille Douai, France. Examinateur.
  • Dr. Inbar Fijalkow, Université de Cergy-Pontoise, France. Examinatrice.
  • Dr. Jean-Marie Gorce, INSA de Lyon, France. Examinateur.
  • Dr. Ligong Wang, CNRS, France. Examinateur.
  • Dr. Guillaume Villemaud, INSA de Lyon, France. Directeur de thèse.
  • Dr. Samir M. Perlaza, INRIA, France. Encadrant de thèse.
  • Dr. Ronan Cosquer, DGA, France. Invité.

CITI Seminar of Yann Orlarey (Grame, Lyon) on May 6 at 10:30am

Title: Contributions to symbolic music representation, digital lutherie and music programming languages

Date and Place: 06 / 05 / 2019 10:30 in TD-C

Host: Florent de Dinechin

The presentation aims to give an overview of the research activities in Computer Music carried out at Grame (Centre National de Création Musicale) in Lyon. These activities include symbolic music representation (with the Guido and INScore projects), new digital lutherie and music programming languages. In particular, we will present Faust ( and, a synchronous functional programming language specialized in real-time sound synthesis and signal processing. The talk will conclude with some live demos of Faust, showing how it can be used for a wide variety of audio applications, from small embedded systems to procedural audio on the Web, as well as musical instruments on smartphones.

Yann Orlarey is currently the scientific director of Grame. His research work focuses on the design and implementation of programming languages for musical and sound creation, with a particular interest in lambda-calculus, functional programming, and real-time and compilation techniques.

CITI Seminar of Thomas Begin (LIP, UCBL Lyon 1) on April 2 at 11am

Title: Contributions to the Performance Modeling of Computer Networks
Date and Place: 02 / 04 / 2019 11:00 in TD-C
Host: Jean-Marie Gorce and Florent de Dinechin
In this talk, I will present some of my contributions to the fields of performance evaluation and computer networks. I will first discuss a new modeling framework to evaluate the performance of DPDK-based virtual switches in the context of NFV (Network Function Virtualization) networks. Then, I’ll describe a scalable stochastic model to accurately forecast the performance of an IEEE 802.11-based network. Finally, I will introduce an original reduced-state description for multiserver queues that breaks the combinatorial complexity inherent to the classical state description and that can easily handle examples with hundreds of servers.


Thomas Begin received his Ph.D. degree in Computer Science from UPMC (U. Paris 6) 2008. He was a post-doctoral fellow at UC Santa Cruz in 2009. Since 2009, he is an Associate Professor at UCBL (U. Lyon 1) in the Computer Science department. During the 2015-2016 academic year, he was on research leave at DIVA lab – University of Ottawa. T. Begin research interests are in performance evaluation, future network architecture, and system modeling. His principal applications pertain to high-level modeling, wireless networks, resource allocation and queueing systems.

CITI is hiring a PhD Student

Une bourse de thèse à pourvoir sur la télé alimentation d’objets communicants


Title: Nouvelles stratégies de télé alimentation d’objets communicants en utilisant des techniques de formation de faisceau distribuée
Keywords: Communications radio, formation de faisceau, transmission de puissance sans fil, synchronisation, automatique
Location: CITI laboratory, INSA Lyon, France
Funding: 3-year
Contact: Florin Doru HUTU <>

Cette thèse adresse le problème de la synchronisation et de la mise en cohérence de phase des sources distribuées géographiquement. L’application envisagée est celle de la transmission de puissance sans fil en mettant en place des stratégies de type formation de faisceau distribuée. Ce projet souhaite aborder la problématique de la transmission de puissance sans fil vers un objet communicant à faible ressources énergétiques aussi bien de point de vue système de communication mais aussi du point de vue automatique. En automatique, le problème traité ici s’apparente à celui de la synchronisation d’un réseau de systèmes à retard ou bien à celui du suivi de trajectoire de référence. Les outils théoriques appliquées à ce scénario concret seront la commande de systèmes multi-agents, la commande de système à retard et l’observation de retard. Ces stratégies seront adaptées pour répondre aux contraintes matérielles des instruments de génération et d’analyse des signaux du laboratoire CITI. En effet, les « transcepteurs » vectoriels de signaux (VST) PXI-5646 de Nationals Instruments sont ciblés dans un premier temps pour ensuite passer à une échelle supérieure en utilisant la plateforme CorteXlab.

More information here.

PhD Defence: “Déploiement et ordonnancement de réseaux de capteurs sans fil pour le suivi de la pollution de l’air”, Ahmed BOUBRIMA, Chappe Amphitheater, CITI, 12th of March 2019, at 10h00


Déploiement et ordonnancement de réseaux de capteurs sans fil pour le suivi de la pollution de l’air


Les réseaux de capteurs sans fil (RCSF) sont largement utilisés dans les applications environnementales où l’objectif est de détecter un phénomène physique tel que la température, l’humidité, la pollution de l’air, etc. Dans ce contexte d’application, l’utilisation de RCSF permet de comprendre les variations du phénomène et donc être en mesure de prendre des décisions appropriées concernant son impact. En raison des limitations de ses méthodes de suivi traditionnelles et de sa grande variabilité spatiale et temporelle, la pollution de l’air est considérée comme l’un des principaux phénomènes physiques qui restent à étudier et à caractériser. Dans cette thèse, nous considérons trois applications concernant l’utilisation de RCSF pour le suivi de la pollution de l’air : la cartographie en temps réel de la qualité de l’air, la détection de dépassements de seuils des polluants et la correction de modèles physiques qui simulent le phénomène de dispersion de la pollution. Toutes ces applications nécessitent de déployer et d’ordonnancer minutieusement les capteurs afin de mieux comprendre la pollution atmosphérique tout en garantissant un coût de déploiement minimal et en maximisant la durée de vie du réseau. Notre objectif est de résoudre les problèmes de déploiement et d’ordonnancement tout en tenant compte des caractéristiques spécifiques du phénomène de la pollution de l’air. Nous proposons pour chaque cas d’application une approche efficace pour le déploiement de noeuds capteurs et puits. Nous proposons également une approche d’ordonnancement adaptée au cas de la correction de modèles physiques. Nos approches d’optimisation prennent en compte la nature physique de la pollution atmosphérique et intègrent les données réelles fournies par les plateformes existantes de suivi de la qualité de l’air. Dans chacune de nos approches d’optimisation, nous utilisons la programmation linéaire en nombres entiers pour concevoir des modèles d’optimisation adaptés à la résolution de petites et moyennes instances. Pour traiter les grandes instances, nous proposons des heuristiques en utilisant des techniques de relaxation linéaire. Outre nos travaux théoriques sur le suivi de la pollution atmosphérique, nous avons conçu et déployé dans la ville de Lyon un réseau de capteurs de pollution économe en énergie. Sur la base des caractéristiques de notre système et des jeux de données de la pollution atmosphérique, nous avons évalué l’efficacité de nos approches de déploiement et d’ordonnancement. Nous présentons et discutons dans cette thèse les résultats d’évaluation de performances ainsi que des lignes directrices pour la conception de systèmes de suivi de la pollution de l’air. Parmi nos principales conclusions, nous soulignons le fait que la taille optimale du réseau de capteurs dépend du degré de variation des concentrations de pollution dans la région de déploiement.



  • Marcelo DIAS DE AMORIM, Directeur de recherche, CNRS, Rapporteur
  • Andrzej DUDA, Professeur des universités, Grenoble INP-ENSIMAG, Rapporteur
  • Aline CARNEIRO VIANA, Chargée de recherche HDR, INRIA, Examinatrice
  • Isabelle GUERIN-LASSOUS, Professeur des universités, Univ. Lyon 1, Examinatrice
  • Thomas NOEL, Professeur des universités, Université de Strasbourg, Examinateur
  • Hervé RIVANO, Professeur des universités, INSA de Lyon, Directeur de thèse
  • Walid BECHKIT, Maitre de conférences, INSA de Lyon, Co-directeur de thèse
  • Claire CHAPPAZ, Atmo Auvergne-Rhône-Alpes, Invitée

CITI Seminar of Eddy Caron (LIP, École Normale Supérieure de Lyon) on March 19 at 11am

Title: Once upon a time … the deployment
Date and Place: 19/03/ 2019 11:00 in TD-C
Host: Jean-Marie Gorce and Florent de Dinechin
In large distributed systems the resource managements is one key of the efficient. And the deployment of the elements on resources are hidden everywhere, across the network, across the virtualization, across many infrastructures, etc. Through 6 stories we will discover many points of view of the deployment. First adventure, we will see how to deploy a middleware with self-stabilization skill. In the second story, be afraid, we will see how to deploy a secure Cloud Infrastructure. In the following story, we will introduce a deployment tool for reproducibility. The licenses deployment is another weird story with a lot of mysteries. An unbelievable story to deploy a data-driven microservices infrastructure. And finally, we will try to clear up the Fog deployment.


Eddy Caron is an Associate Professor at Ecole Normale Supérieure de Lyon and holds a position with the LIP laboratory (ENS Lyon, France). He is a member of AVALON project from INRIA and Technical Manager for the DIET software package. He received his PhD in C.S. from University de Picardie Jules Verne in 2000 and his HDR (Habilitation à Diriger les Recherches) from the Ecole Normale Supérieure de Lyon in 2010. His research focuses on distributed computing environment, from P2P to Grid, Cloud and Edge computing. At the middleware level, he deals with a large scope of subjects (scheduling, workflow management, data management, energy management, security, software management, etc.)  with the same point of view of the resource magement in heterogeneous environments.
He is involved in many program committees (as HCW, IPDPS, ISPA, CloudTech, etc.). Since 2000, he contributed to more than 30 articles in journal or book chapter and more than 80 publications in international conferences. He was co-chair of the GridRPC working group in OGF. He was coordinator of two french ANR project (LEGO and SPADES). He was workpackage leader in the European project Seed4C around the security. He is the supervisor of 15 Phd (4 in progress). He teaches Distributed system, Architecture Operating System and Network, Grid and Cloud, etc. Moreover he was the Co-funder and Scientific Consultant of a company (SysFera). Deputy Director in charge of call for projects, research transfert and international affairs for the LIP Laboratory.  See for further information.